1. Field of the Invention
The present invention relates generally to cleaning implements and methods, and more particularly, to a method and implement for cleaning the fixed spring-contacts of a television tuner.
2. Description of the Prior Art
Multiple position television tuners generally fall into two categories, namely, wafer tuners and drum tuners. Tuners of the latter type include a set of fixed, spring-contacts which are selectively engaged by one of a series of channel selector strips arranged about the circumference of a rotatable drum. The channel selector strips carry a set of electrical contacts to which a series of coils are attached. Upon rotation of the drum, one of the coil-carrying channel selector strips is brought into engagement with the fixed, spring-contacts whereupon the coils are placed in the frequency determining circuit of the tuner so as to condition the television receiver to receive signals on a desired channel.
The channel selector strips usually contain eight contacts, and the drum assembly generally contains thirteen such strips about its circumference. Thus, the drum typically includes some 104 contacts which will selectively be brought into engagement with eight, fixed spring-contacts on each full rotation of the tuner shaft. After the tuner has been in use for a period of time, a film of dirt and other contaminants collects on all of the contacts thereby interferring with proper circuit connections which are necessary to optimum tuner performance. When this contaminant layer begins to build up to the point where it interferes with the switching function of the tuner, the tuner becomes "noisy" in that flickering and "snowy" pictures occur as well as poor audio whenever the tuner shaft is moved from one channel to the next. The dirt and contamination can also build up to the point where certain channels cannot be received at all.
When a television tuner of the drum-type has become coated with the dirt and contaminant film mentioned above, it is necessary to clean all of the contacts in order to restore proper tuner performance. In the past, the tuner contacts have been cleaned using a solvent wash which will remove most of the contaminant particles but is ineffective in removing some of the more dense films and dirt layers. To remove this material, a fine abrasive sandpaper or eraser can be used. The contacts of the channel selector strip of the drum can be easily cleaned using this technique, but it is often difficult or impossible to reach the fixed, spring-contacts of the tuner without removing several of the channel selector strips from the drum. This involves a considerable amount of time and effort, and there is also the possibility of inadvertently damaging the individual strips on removal or reinsertion as well as the possibility of replacing the strips in the wrong position.
As a result of the above problems, periodic cleaning and overhaul of television tuners is generally expensive, time-consuming, and presents considerable difficulties even to experienced repairmen.